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Discussion Starter · #1 ·
Hi everyone,

I would like to ask a couple of questions regarding the Design Corse CNC rear hub, which I believe it is pretty much the same as the one Jetprime is currently selling.

I managed to get hold of a brand new one for my F4 750 and I was planning on replacing the stock one with it. However, the mechanic wasn't able to fit it and he told me that his hub requires the 2010+ axle, as the pre 2010 axle is slightly shorter.

I was told this hub was a direct replacement for mine. At the moment, I have the stock axle and hub, and stock rear sprocket set up (no quick change). Researching the forum I found that indeed, the new 2010+ MV Agusta hub requires the second regeneration axle as well. Same as the 2010+ DC hub.

My question is, what would you recommend me in this situation? I thought of selling the hub but before doing that I wanted to ask if there is any way of fitting it on my bike.

At the moment, the alternatives I see are:

- 1st gen axle and hub kit from MV (which is like £700 plus VAT). Part number 8000B4954. Crazy money for a hub that will eventually fail.

- Second gen axle plus Design Corse hub. Would this work with an F4 750 stock sprocket (no quick change)? The mechanic told me it won't work without the quick change sprocket config. Any idea?

- 1st gen axle plus Mitch hub? Again, would the Mitch hub be a direct replacement of the stock pre 2010 hub? Can I keep the original sprocket? I would have to sell this hub first before investing on a Mitch hub.

Pictures of the hub below.

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Thanks for your help!
 

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Old Wing Nut
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Yes..the Design Corse hub was made by JetPrime...and now sold by JetPrime. You could ask them for information.
The Mitch hub works with your axle and sprocket carrier set-up.
I believe the original sprocket carrier and later "quick change" carriers are interchangeable... the later 2010 use a different "top hat" spacer which is available separately. I could be mistaken there and am sure someone will chime in with a correction if I am.
So... you could just get a 2010 axle and spacer?
 
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Discussion Starter · #3 ·
Thanks esq'z me.

My first thought was that perhaps a smaller spacer would have worked, but I am just guessing. I emailed Jetprime like 3 weeks ago and never got a reply :/ I will send another one and let's see what they say.

You think a 2010 axle and different spacer would work? It sounds like a good option to be honest, it is something I didn't consider. It should be easy to get old of a 2010 axle, not that sure about the spacer though. I would like to think that JetPrime could sell me one of those?

I am honestly trying to find the simplest solution and if I can avoid the hassle of selling the hub, even better. Thanks for your suggestion, noted.
 

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I’d get a Mitch hub. My MV hub got destroyed and a Mitch Hun has been flawless ever since. The other cool part is you can contact him here and he’s super chill.
 

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Jetprime should also have the pre-2010 hub, maybe you can exchange it.
 
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Both axles are the same length.
It is the bearing lands on the axles are different length as my photo shows.
You can still use the original axle with your new hub.
Just make sure you check the new spacer is the correct OD where it sits in the
recess on the sprocket carrier.
Automotive exhaust Cylinder Nickel Gas Auto part
 

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Discussion Starter · #7 ·
Thanks all for your help.

I found this old post and in here, BG Wells mentions:

A little while ago Design Corse released their CNC'd upgraded and replacement hub for the Y10+ MV Agusta F4 and Brutale B4 models...http://www.mvagusta.net/forum/showthread.php?p=1004857#post1004857

Well they have now developed their CNC'd upgraded and replacement hub for the 'pre 2010' MV Agusta F4 and Brutale B4 models now.


What I understand from this is that DC originally released two hubs, one pre 2010 and an other 2010 onwards. And it seems like the hub I bought is 2010+. Does anybody know what the difference was between the two? I can't find info online.

Both axles are the same length.
It is the bearing lands on the axles are different length as my photo shows.
You can still use the original axle with your new hub.
Just make sure you check the new spacer is the correct OD where it sits in the
recess on the sprocket carrier.
Thanks mitchy. I have watched Youtube this video on YouTube showing how to to fit your hub and I understand now what you mean with the correct OD. Based on what the mechanic told me, the spacer I have is adding more separation than what it should and that's probably why he couldn't fit the nut and clip properly. A smaller spacer perhaps would do? The spacer I have looks bigger than the one on that video for your hub.

I am going to drop another email to Jetprime and hopefully someone there can help me, and perhaps supply the right spacer if that's the only thing I need.
 

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There is 2 OD dimensions on the spacers
Early 750's the OD is 65mm
1000 models-on the OD is 76mm.
The spacer must sit in the recess on the Sprocket carrier.
Otherwise the sprocket nut will not screw up far enough to allow the safety clip to be fitted.
You may have to get the spacer machined down to the correct size or order one from Jetprime.
 

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Discussion Starter · #9 ·
mitchy,

Thank you for your help. I think I am slowly understanding what the problem is here.

I measured the spacer I have and the OD is 76mm. Based on what you said, obviously this won't fit on my bike with the first gen axle.

There is still something I am not sure about. Form the pictures I see, there seems to be two different shaped spacers. One is completely flat (which seems to be the one used in the pre 2010 models), and the other is like the one I have which its OD is 76mm, pictures below.

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I was trying to fit the hub on a 1st gen axle with the new spacer. It makes sense now what the mechanic said, a flat spacer would have allowed the safety clip to be installed and nut tighten.

Could someone please clarify something? Are the pre MV Agusta 2010 and 2010+ hubs the same? DC/Jetprime seems like they manufactured two different hubs back in the day, but now they only offer one model on their site. Also, mitchy, I can see your hub for sale at mygpracing.com and there is a drop down list to select "up to 2009" and "2010+". Is it just the spacer what's different?

Apologies for all these questions! I just need to make sure that next time I take the bike to the shop they will have everything they need to fit it, I don't want to waste their time. If only I could do this myself!

Also, Jetprime replied to my email from last night. Zero helpful. First reply was "Good morning, This hub is compatible with all MV on the market" and the second one "I can't understand, you already have everything you need". Fair enough that they didn't sell me the hub but since they manufactured it I was hoping they could at least show a bit of interests in helping me... anyway, good to know, I won't buy anything from them.
 

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Discussion Starter · #10 ·
Ok, I managed to find that the main difference between hubs is the setup of the bearings inside.

Would the following setups work on my bike?

F4 750 OEM sprocket carrier - 65mm OD - DC hub - 1st gen axle
F4 750 OEM sprocket carrier - 76mm OD - DC hub - 1st gen axle (this I already know it doesn't)
F4 750 OEM sprocket carrier - 65mm OD - DC hub - 2nd gen axle


Thanks all for your help!
 

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There are several key differences between the First Gen (up to 2009) hub and the Second Gen (2010+) hub).
The spacer for the First Gen was a flat washer. The spacer for he second Gen is a Top Hat spacer that must slide into the new hub.
The OD of the spacer changed from 65mm to 76mm and that prevents the later spacer from fitting into the recess on the back of a First Gen carrier.

The most significant difference is that the Second Gen hub has a double row of bearings versus the single row of the First Gen hub. The second row of bearing required the Second Gen axle to be remanufactured with a larger hardened bearing carrier surface. This arrangement gave the Second Gen system more longevity.

Here is a cross-sectional view of a Second Gen Hub and Axle:

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Do not forget the differences between the early 1srt gen sprocket carrier where the cushions are in the actual sprocket, and the later 1st gen where the sprocket is on a quick change carrier.
I think that is the source of his spacer confusions. He has the original early design.
 

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Discussion Starter · #13 ·
The OD of the spacer changed from 65mm to 76mm and that prevents the later spacer from fitting into the recess on the back of a First Gen carrier.
Thanks silentservice703 for that.

I think, as mitchy already pointed out, the issue is the spacer. Mine has a OD of 76mm and has a hat shape. It is not flat. If I am planning on keeping the sprocket carrier design the ring must have an of of 66mm, regardless of what sprocket config you have.

Having a look at my sprocket I can see the recess you mention:

488015


So the 66mm OD spacer must fit in that recess. That makes sense, the 76mm obviously didn't fit and pushed the sprocket slightly forward, not leaving space to fit the safety clip.

I had a look at this video and at 9:31 you can see how the ring fits into the small recess of the sprocket carrier:

488017



Well, I think it is all 100% clear now. I need the correct spacer and the hub should fit with the 1st gen axle and sprocket carrier.
 

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Discussion Starter · #14 ·
Do not forget the differences between the early 1srt gen sprocket carrier where the cushions are in the actual sprocket, and the later 1st gen where the sprocket is on a quick change carrier.
I think that is the source of his spacer confusions. He has the original early design.
Thanks esq'z me, this is correct.

To be honest, it would be so much easier if I could do this work myself. Any doubts, take pictures and upload here :)

I wish I had a garage!
 

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You have to use the stepped spacer on the Jetprime hub.
A flat spacer will not work
Have the stepped spacer machined down to 65mm to fit into the recess on the sprocket.
My hub is different and uses a flat spacer.
The stepped spacer holds the stack together if that makes sense.
 

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Discussion Starter · #17 ·
You have to use the stepped spacer on the Jetprime hub.
A flat spacer will not work
Have the stepped spacer machined down to 65mm to fit into the recess on the sprocket.
My hub is different and uses a flat spacer.
The stepped spacer holds the stack together if that makes sense.
Thanks mitchy, understood. I will chase Jetprime, if their hub fits all MVs they should have an OD 65mm spacer. Last question, I promise 😀 Would you recommend a 2nd gen axle? Do the bearing lands affect in anyway the hub's performance?


I shudder at the sound of a stepped spacer knowing that was the demise of my hub and almost death.
I can imagine... glad to hear you are ok!
 

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Discussion Starter · #19 ·
You can use the early axle.The bearing land is wide enough to sit on the inner ball race to provide support.
Thanks mitchy (y)

The support from Jetprime told me that they don't supply any spacers with their hub. Their response below:

Our hub is sold without spacers
you have to use the original diameter 76
We have been selling them like this for 10 years and no one has ever had problems with assembly
I recommend you to buy the latest update of this MV code because they have changed the treatment and it is more resistant


It seems like not many early F4 750s owners have ever bought this hub. With the early sprocket carrier set up, no chance you can fit the hub with the 76mm spacer...

Anyway, cheers all for your help. Now I will try to find someone that can machine down my 76mm spacer to 65mm...
 

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Discussion Starter · #20 ·
Hi all,

I finally got the spacer machined down to 65 mm. It fits now in the recess of the sprocket carrier however there is a bit of play, it doesn't fit tight. Could someone please confirm this is the way is supposed to look like? I would like to think that due to heat and parts expanding this is the way it should be.

I have measured the OD and it is definitely 65 mm. If you look closely, there is a 1-2mm gap between the spacer and the sprocket recess wall.

Eye Automotive tire Architecture Laundry room Rim



I am also trying to get hold a 2nd gen axle. I have been told my axle needs replacing so might as well get a 2nd gen one for my F4 750.

While I can't find a new one anywhere, I found this one on eBay: MV Agusta F4 1000 Rear Wheel Axle Shaft 2010 | eBay . Does it look in decent condition to be fitted with a new hub and sprocket?

Sorry for all the dumb questions! I am far from an expert unfortunately and since I am paying someone to fit the parts, I need to make sure everything is on point!

Thanks!
 
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